The term “ladybug” is commonly used to describe a small, domed beetle that is often red with black spots. These insects are more accurately referred to by entomologists as lady beetles or ladybird beetles. They belong to the family Coccinellidae, a widespread group found across the globe. This single family contains many thousands of distinct species.
Understanding Ladybug Diversity
The Coccinellidae family boasts over 6,000 described species worldwide. In North America alone, the number of lady beetle species exceeds 480. This diversity means that the typical image of a red beetle with a few black spots represents only a fraction of the family’s members.
Species are differentiated by characteristics extending far beyond simple spot counting. Adult lady beetles typically range in size from 1-millimeter specimens up to 10 millimeters in length. Coloration is highly variable, encompassing red, orange, yellow, brown, black, and metallic blue-green.
Spot patterns, or their complete absence, serve as an important identifier, though this trait can vary within a single species. Some lady beetles feature elaborate patterns of black spots, while others are entirely black with red or orange markings. The shape of the beetle’s body, which can be rounded, oval, or slightly oblong, also helps distinguish types.
Common Beneficial Native Species
Among native lady beetles, the Convergent Lady Beetle (Hippodamia convergens) is widely recognized and beneficial to agriculture. This species is slightly oblong, ranging from 4 to 7 millimeters in length, and has orange or reddish wing covers. Its name comes from the two white lines that converge on the black section behind its head.
The Convergent Lady Beetle typically has up to 13 black spots on its wing covers, though it can sometimes have fewer or no spots. Both the larvae and adults are voracious predators, primarily consuming aphids, which are common plant pests. A single adult can consume about 100 aphids per day, making it a valuable ally for pest control.
Another important native species is the Two-Spotted Lady Beetle (Adalia bipunctata), which measures 4 to 5 millimeters long. The common form features a red-orange body with one black spot on each wing cover. This species displays color variations, including forms that are black with four red spots or those with up to six spots.
The Two-Spotted Lady Beetle is native to both North America and Europe and is highly effective at controlling soft-bodied pests like aphids, scale insects, and psyllids. Like the Convergent Lady Beetle, the larvae are also predatory, ensuring pest removal throughout the insect’s life cycle. These native species are often threatened by non-native competitors.
Identifying the Invasive Harlequin Lady Beetle
The Harlequin Lady Beetle (Harmonia axyridis), also known as the Asian Multicolored Lady Beetle, is a non-native species that has become widespread and problematic. It is highly polymorphic, meaning its appearance is extremely variable and often leads to confusion with native species. It typically measures between 5 and 8 millimeters long.
The most common form is yellow, orange, or red with a variable number of black spots, ranging from zero to 22. A more consistent identification feature is the “M” or “W” shaped black marking on the plate behind its head. This pattern is unique among most lady beetles in invaded regions. The species was originally introduced as a biological control agent for aphids.
The Harlequin Lady Beetle is considered invasive because its large size and voracious appetite allow it to outcompete native lady beetles for food. It actively preys on the eggs and larvae of native species, contributing to their decline. The beetles often aggregate in large numbers on the sunny sides of buildings in the autumn, seeking shelter to overwinter, which can make them a nuisance indoors.